I'm trying to migrate mailboxes from Exchange 2007 to Office365. Going thru the online guide to do a "cutover" migration was going ok until the point where you have to test "Autodiscover". If I run the MRCA, it fails when selecting "Autodiscover". If I select to "Manually Select server settings" the test will pass with a warning about the certificate.
Outlook Web Access works ok with all users and no certificate errors in the browser. After doing some research online for this problem, I added a CNAME for autodiscover to our DNS record and also tried opening port 80 on our firewall temporarily also, but this didn't solve issue. I inherited this Exchange server and am not an expert on it by no means. Attached are results from the MRCA test.